In many businesses, organizations or public areas, security systems are employed to control access to the physical facilities or resources, and to safeguard authorized and unauthorized visitors. Security risks may be managed by controlling access by specified individuals based upon a specific set of criteria, such as time of day or day of the week.
In a typical physical-access controlled environment, a physical security system may include one or more functional devices, such as: entry lock mechanisms; entry open/close sensors; video surveillance cameras; microphones; credentials, such as some form of electronic or physical identification of a device or individual; credential identification input devices, such as a badge reader, PIN number keypad or biometric detector; communication and connectivity devices, such as door control panels; credential verification devices; policy-based access control devices, such as access control panels; credential and policy creation servers; a monitoring, event logging, and alarm reporting server; and a permission database defining which users have access to which facility, and when.
The control panel is typically located in close proximity to an entrance. Many control panels used in a typical physical-access controlled environment have a full or partial credential list. As facilities have multiple entrance points, each often with a corresponding control panel, it requires considerable work to ensure that all control panels are up to date. There are some access control systems that offer centralization of the data that would otherwise be distributed in multiple control panels. In these systems, the control panels pass credential information on to a central device such as a server for credential verification and policy enforcement. The server, if granting access, will then send an ‘access granted’ signal to the appropriate control panel, which would then forward a signal to a relay for controlling the opening of a door.
It is common for access control devices, such as badge or card readers, electro-mechanical locks, and door sensors, to be connected by a serial Wiegand or RS485 connection to a door control panel. The functional devices typically communicate via a simple signaling protocol, which in many cases is specific to a single vendor.